Sent while driving at 80mph, eating a Big Mac and using my knee to steer.

I just confirmed with Lucas at CMMG about their compatibility with DPMS lowers. And yes, CMMG uppers will work with DPMS lowers. It's the Armalite products that you should check on compatibility with. Armalite AR-10 lowers will only accept Armalite style magazines and the take down pins are different sizes , as well.
Bobby~